Export "finish" return value to Python

This patch changes the Python "stop" event emission code to also add
the function return value, if it is known.  This happens when the stop
comes from a "finish" command and when the value can be fetched.

The test is in the next patch.

Reviewed-By: Eli Zaretskii <eliz@gnu.org>

diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi
index 4ae72716f56bd6c7cf2a169dd9787c7826321bb3..4ca3ae4eca4c17bec51ebcc5b10214224512e17b 100644 (file)
--- a/gdb/doc/python.texi
+++ b/gdb/doc/python.texi
@@ -3813,6 +3813,12 @@ corresponding MI output (@pxref{GDB/MI Async Records}).
 
 A dictionary was used for this (rather than adding attributes directly
 to the event object) so that the MI keys could be used unchanged.
+
+When a @code{StopEvent} results from a @code{finish} command, it will
+also hold the return value from the function, if that is available.
+This will be an entry named @samp{return-value} in the @code{details}
+dictionary.  The value of this entry will be a @code{gdb.Value}
+object.
 @end defvar
 
 Emits @code{gdb.SignalEvent}, which extends @code{gdb.StopEvent}.

diff --git a/gdb/infcmd.c b/gdb/infcmd.c
index c1fdbb300c67c15893383e7a4762f062958c6ec4..ac41ebf11b4fa14c68f76b1dcc36f0bf729d69bf 100644 (file)
--- a/gdb/infcmd.c
+++ b/gdb/infcmd.c
@@ -1484,23 +1484,6 @@ get_return_value (struct symbol *func_symbol, struct value *function)
   return value;
 }
 
-/* The captured function return value/type and its position in the
-   value history.  */
-
-struct return_value_info
-{
-  /* The captured return value.  May be NULL if we weren't able to
-     retrieve it.  See get_return_value.  */
-  struct value *value;
-
-  /* The return type.  In some cases, we'll not be able extract the
-     return value, but we always know the type.  */
-  struct type *type;
-
-  /* If we captured a value, this is the value history index.  */
-  int value_history_index;
-};
-
 /* Helper for print_return_value.  */
 
 static void

diff --git a/gdb/python/py-stopevent.c b/gdb/python/py-stopevent.c
index 61d93727b31a149c6b48c2beda3c03abcc1cbf5f..fcaebe26f13c0cdd8f706035dc56f8f68878f334 100644 (file)
--- a/gdb/python/py-stopevent.c
+++ b/gdb/python/py-stopevent.c
@@ -20,6 +20,7 @@
 #include "defs.h"
 #include "py-stopevent.h"
 #include "py-uiout.h"
+#include "thread-fsm.h"
 
 gdbpy_ref<>
 create_stop_event_object (PyTypeObject *py_type, const gdbpy_ref<> &dict)
@@ -45,6 +46,7 @@ static gdbpy_ref<>
 py_print_bpstat (bpstat *bs, enum gdb_signal stop_signal)
 {
   py_ui_out uiout;
+  struct value *return_value = nullptr;
 
   try
     {
@@ -55,6 +57,10 @@ py_print_bpstat (bpstat *bs, enum gdb_signal stop_signal)
        {
          async_reply_reason reason = tp->thread_fsm ()->async_reply_reason ();
          uiout.field_string ("reason", async_reason_lookup (reason));
+
+         return_value_info *rvinfo = tp->thread_fsm ()->return_value ();
+         if (rvinfo != nullptr && rvinfo->value != nullptr)
+           return_value = rvinfo->value;
        }
 
       if (stop_signal != GDB_SIGNAL_0 && stop_signal != GDB_SIGNAL_TRAP)
@@ -73,7 +79,22 @@ py_print_bpstat (bpstat *bs, enum gdb_signal stop_signal)
       return nullptr;
     }
 
-  return uiout.result ();
+  gdbpy_ref<> dict = uiout.result ();
+  if (dict == nullptr)
+    return nullptr;
+
+  /* This has to be done separately to avoid error issues, and because
+     there's no API to add generic Python objects to a py_ui_out.  */
+  if (return_value != nullptr)
+    {
+      gdbpy_ref<> val (value_to_value_object (return_value));
+      if (val == nullptr)
+       return nullptr;
+      if (PyDict_SetItemString (dict.get (), "finish-value", val.get ()) < 0)
+       return nullptr;
+    }
+
+  return dict;
 }
 
 /* Callback observers when a stop event occurs.  This function will create a

diff --git a/gdb/thread-fsm.h b/gdb/thread-fsm.h
index 90abb5c27f692a7d7ff00dfb72a60f12fcd0c932..ed117719c0d2dbfc8bdc0a776dd5546a7e85c57d 100644 (file)
--- a/gdb/thread-fsm.h
+++ b/gdb/thread-fsm.h
@@ -23,6 +23,25 @@
 
 struct return_value_info;
 struct thread_fsm_ops;
+struct type;
+struct value;
+
+/* The captured function return value/type and its position in the
+   value history.  */
+
+struct return_value_info
+{
+  /* The captured return value.  May be NULL if we weren't able to
+     retrieve it.  See get_return_value.  */
+  struct value *value;
+
+  /* The return type.  In some cases, we'll not be able extract the
+     return value, but we always know the type.  */
+  struct type *type;
+
+  /* If we captured a value, this is the value history index.  */
+  int value_history_index;
+};
 
 /* A thread finite-state machine structure contains the necessary info
    and callbacks to manage the state machine protocol of a thread's